This one is still not exactly the same as your sample. It could be that user1 is the same as user2. For instance both could be mark. In your case that record is not selected and in the sample above it's selected. You could add an extra AND condition to exclude those. You could add: AND user1 != user2

If a query gets more complex and an in query is not possible, then you could execute 2 queries and merge the result.